The present invention concerns a switching device for an electric or electronic apparatus, which is of simple and economic design, and is able to close at least three different contacts of a circuit allowing said apparatus to perform three different functions. The invention concerns more particularly a device of this type for controlling, by means of a single control member, different functions of an electronic timepiece, such as setting the time, setting the date, or adjusting the alarm time of a watch, or the start, stop and reset functions of a chronograph watch, or for activating functions which are not necessarily linked to the passing of time, for example the lighting of the dial or the dive depth indication.
Timepieces provided with several functions generally include several buttons and/or push-buttons, which, via the order and way in which they are handled (short/long application of pressure, slow/quick rotation, etc.), allow instructions to be supplied to an integrated electronic circuit to control a determined function. It is evident that the user must also make an effort to remember the manipulations he has to perform to obtain the desired function. Further, even if certain users are apprised of the technical achievement of a product by its visual appearance, other users may prefer a product with a more discreet aesthetic appearance, i.e. including fewer buttons and/or push-buttons, while providing the same functionality as regards the functions.
The object of the present invention is precisely to provide an electric switching device allowing the number of external control members to be considerably reduced for the same number of functions.
The invention therefore concerns an electric switching device mounted in a case and including a frame having a U-shaped recess each branch of which includes, along an axis parallel to the base of the recess, a through passage for the passage of a control stem which can be actuated by means of a head located outside the case allowing the other end of the stem, located inside the case, to act on at least three electric contacts mounted on a plate extending beyond the frame. The opening of the first through passage, on the side of the head, is circular and has a larger diameter than that of the stem. The stem is guided inside this first passage by an O-ring housed in a groove of a swelling of the stem and abutting against the wall of said through passage. The other end of the stem is guided by the second through passage, on the side of the contacts, the opening of which has an elongated contour of substantially the same width as the diameter of the stem. The stem is held in these two through passages in a neutral position, i.e. without any action on the electric contacts, by means of a helical spring, held on one side in an annular groove surrounding the elongated contour, and compressed on the other side by a washer abutting against a clip engaged in a groove of the stem, said clip itself abutting against the selling of the first through passage. Thus, by exerting pressure on the head of the stem, it is possible to close a first electric contact located along its axis, and by imposing a tilting movement on the head, it is possible to close two other contacts close to the ends of the guide contour. As can be seen, this simple and economical design, allows at least three different switching positions to be obtained with a single control member, as may be necessary for example for the start, stop and reset functions of a chronograph watch.
Other features and advantages of the present invention will appear upon reading the following description of a chronograph watch taken by way of non limiting example with reference to the annexed drawings, in which: